In video systems that include a television, cable box, and video cassette recorder, a user may wish to watch one cable channel while recording another cable channel. Many televisions are now designed to be cable ready. By using a switch called an A/B switch, a user can attach the television either directly to the cable or to the output of the video cassette recorder, which is connected to the output of the cable box. This gives the user the capability of recording one cable channel and viewing another cable channel on the television. For example, an unscrambled channel on cable can be viewed on the television while a VCR records a scrambled channel that is unscrambled by the cable box.
The A/B switch solves the problem of watching one channel on television while recording another channel on a VCR; however, the A/B switch is a manual switch and the user must physically operate the A/B switch. The user would prefer to use a remote controller to control the video system to be able to view one channel while recording another.
Another problem is that when a cable box is used, only one channel is tuned at any one time to appear on the channel 3 output of the cable box. Thus for users without an A/B switch, it is only possible to view and or record one channel at a time. Thus a user is not able to record on channel 30 while viewing a program on channel 24, for example.
Another problem is that if an over-the-air antenna and a cable or a satellite receiver are both used for reception, then it would be desirable to be able to record a channel from either source while viewing a channel from either source. An A/B switch does not provide this capability and in any event requires manual switching.